by Louis Sirico
One of the quickest and easiest ways to get started using RFID technology is to replace a barcode printer with an RFID printer/encoder. With minimal programming, an RFID tag can be encoded with a unique identifier at the same time the label is printed. The label is hand-applied to a product, creating an RFID-tagged asset. This technique is commonly referred to as "slap and ship." The primary drawback to this approach is that it creates a bottleneck except at very low volumes, typically 1,000 tags per day or fewer. An RFID printer/encoder is valuable for exception handling, such as replacement of a failed tag or a product that requires special handling.
RFID-enabled visibility points have a tremendous effect on efficiency. Wal-Mart has reported a 30-percent reduction in out-of-stocks compared to its previous process, which was based on using a hand-held barcode scanning device. This alone equates to billions of dollars in savings to the world's largest retailer and its suppliers.
Other key benefits include:
• Lower labor rates . Manual barcode scanning is time-consuming. Receiving a truckload of loose cases can take a single operator with a hand-held barcode scanner up to 40 hours to check in. Using RFID-enabled portals reduces the time to just a few hours.
Most relocation processes include a step where personnel scan one or more barcodes to capture that movement has taken place. RFID makes this process automatic simply by capturing where products were last seen.
• Reduced errors. RFID tags that contain electronic product codes (EPC) are serialized; universal product codes (UPC) barcodes are not. If the same UPC is scanned twice, it is counted twice. If the same RFID tag is read twice or more, it is only counted once. This greatly reduces costly inaccuracies in inventory counts caused by improper barcode scanning.
• Improved data. When moving from manual barcode-based processes to RFID-enabled processes, the data feeds switch from batch processing to real time. This allows proactive decisions based on movement. Additionally, having real-time visibility helps improve handling of time-sensitive products, such as those with expiration dates.
Radio frequency identification (RFID) is changing the way companies do business. Cutting through all the hype, the basic business benefit of RFID technology is improved asset visibility in a global supply chain. For companies pursuing lean, RFID provides fewer line shortages due to inventory foul-ups, fewer man-hours spent on monitoring parts inventory or work in process, the ability to automatically collect data on defective and returned parts, and much more.
A basic RFID system consists of tags, which are unique identifiers attached to every part or assembly; an interrogator (i.e., "reader") to send and receive RFID signals; antennas, which are placed near where tagged parts will pass and that broadcast or detect radio frequency signals to or from the tags; and a processor to handle the data.
The primary function of an RFID reader is to report changes to its environment. A change in state is called an "event."
• A new-tag event occurs when a tag appears to a reader for the first time.
• A visibility-changed event occurs when the visibility of a tag changes for a read point.
• A tag-not-visible event occurs when a tag is no longer visible to any read point.
A reader captures events along with the date, time and data from the RFID tag that caused the event to occur. In addition to the four basic RFID components, more sophisticated RFID systems incorporate monitoring and sensing devices such as electronic switches, photo-eyes and motion sensors. The events from these devices are combined with the RFID-related events for improved decision making.
RFID systems are often connected to warehouse automation systems that are made up of devices such as programmable logic controllers. The events generated by the RFID system trigger these devices to perform various operations.
Determining where RFID technology should be applied within a supply chain means asking where you can benefit from asset visibility. Typically, asset visibility is desired when movement occurs: The product came in the door, the product is on the shelf, etc. Chances are someone in your organization asked this question when designing the manufacturing plants, distribution centers and other locations across your supply chain. Most likely, these locations have some type of automatic identification technology already in place, such as a barcode scanner. Manual methods of identification are very common. The standard by which all other identification methods are measured is still the person with paper and clipboard counting what he or she sees.
Contrary to what you may have read, RFID is not going to replace barcodes completely. Just as human-readable information is still used with barcodes, RFID technology will complement barcode technology. However, there are five primary advantages to RFID over barcodes: speed, large read distances (up to 3 meters), simultaneous rather than sequential scanning, no line of sight to tag required, and durability.
There are numerous locations within a facility to apply RFID technology. This article will focus on some of the more common industrial locations and the benefits companies are realizing from improved asset visibility using RFID technology.
For the purposes of this article, the industrial locations described are assumed to be in such places as warehouses, distribution centers or manufacturing plants. These facilities are common in most supply chain operations.
An RFID-enabled portal is a doorway through which goods travel, and it provides the best opportunities to realize the technology's benefits. There are several different configurations of portals, but the most common is the dock door.
As pallets and cases of RFID-tagged items move through the portal, they may be rapidly identified even when traveling via materials-handling equipment, such as a forklift. Often, it's important to know the direction in which the product is traveling. Directionality can be determined by using one of two methods: calculated or assumed.
Calculated directionality is the most accurate method to determine the path of an item. This works by comparing the outputs of two or more read points. When a tag is seen in read zone A and then in read zone B, it can be determined that the tag is moving from A to B.
Assumed directionality is the simpler of the two methods but not always possible or accurate. For example, if a dock door is dedicated for only outbound shipping functions, it can be assumed that when a tag is seen there, it is traveling out through the door. The problem with this assumption is that goods are often loaded, unloaded and reloaded again. Assuming directionality does not take this process into account.
Examples of RFID-enabled portals include:
• Inbound receiving doors . RFID-enabled receiving doors can provide automatic inventory updates for
received goods. Retailers use RFID for verification that the products received match the contents of the advance shipping notice. By combining RFID with display terminals, operations personnel can be instructed in what to do with the product.
• Outbound shipping doors. Verification is the key benefit to RFID-enabled outbound shipping doors. Not only can RFID ensure that goods are being loaded onto the right truck, it can also verify that products are loaded in the proper sequence. This is especially important with full pallets on trailers with multiple destinations. It prevents one company from having to move another company's product to access its pallet, thereby saving time.
• Interfacility doors . Multiple facilities may be built next to each other. For example, a manufacturing plant may be located adjacent to a distribution center. Finished goods may be moved from one facility to the other. An RFID portal installed in the routes that connect these facilities can automate the transfer process.
After an item or product is tracked on its journey into the warehouse, it's important to know where it resides in the facility for easy retrieval and verification. Although still too expensive for most companies to implement throughout a warehouse, some companies are RFID-enabling their storage locations. By using a shelf antenna for small goods or location antennas behind larger items, inventory can be automatically updated as products are picked or put away. Not only does this improve inventory tracking, it also eliminates operators from scanning barcodes or manually writing product relocation tickets, which have to be keyed-in later. Operators can be given instant feedback when putting goods in the wrong location or, as some advanced business models have demonstrated, products can be placed in any open location. Because the RFID technology instantly captures where the product is placed, you can always find it.
• Hand-held RFID devices. Working with an RFID-enabled hand-held unit is not like working with a hand-held barcode scanner. An RFID hand-held unit will scan multiple RFID tags in its read field. Hand-held RFID readers are being used in a way that barcode scanners can't--at the product location. With this function, when the RFID reader is placed in "search" mode, it emits a tone that beeps more rapidly the closer the device gets to the tag, enabling the user to quickly locate a specific part amongst a stack of parts. Because many of these units perform both barcode and RFID scanning functions, some companies are opting to replace older units with newer, multifunction models that perform both types of scanning.
• Forklift or clamp-truck-mounted RFID readers. Instead of using shelf or location antennas, RFID readers can be mounted onto materials-handling equipment such as forklifts or clamp-trucks. By combining RFID with positional tracking of the equipment, real-time visibility of moving goods is possible. Companies know what the forklift is carrying and where it's going. The primary goal is not only more real-time inventory control, but also a reduction of unnecessary work. System verification can ensure that operators touch the correct product for the correct reason at the correct time, and that they're performing the correct action with it.
• Visibility point . One of the advantages of RFID technology over barcodes is that it does not require a line of sight to scan. If an item traveling on a conveyor is not oriented properly, it can still be read as long as the tag's read zone is designed properly. In some situations, RFID performs so much more rapidly than barcodes that the speed of the conveyor may be increased for faster throughput. RFID equipment is often combined with conveyor diverters to control product flow to the correct destination.
• Tag commissioning. If the tag is already applied to an item traveling on a conveyor, an interrogator can encode the tag. This technique is used for some work-in-
progress management applications. The serial number of the item is encoded on the tag at the first stage. As the tagged product goes through the assembly process, its location can be automatically determined. Depending on the RFID technology in use, products on a conveyor may have to come to a complete stop to allow time for the tag to be encoded.
• Automatic label applicator/RFID encoder. As with barcode printers, automatic label applicators are also being outfitted with RFID technology to encode tags as the label is applied to a product. It's important to compare the speed of the new RFID encoder/applicator to the label applicator in place. The manufacturing line speed may be increased, depending on the unit being installed. The large image at the beginning of this article shows such a system.
An ideal location for asset visibility is at the completion of a pallet being built. What better time to automatically verify the contents of the pallet? If there is a case that shouldn't be included or a product is missing, a visual or audible notice can be given to operations personnel that a problem needs to be corrected. It's also a great time to capture statistics. How long did it take between the tag application and the pallet being completed? Data capture at this stage makes sense because the pallet is often bound for the next step in the process: staging or outbound shipping.
Staging or holding areas also are important locations for asset visibility. Knowing that a product was just received but not yet put away can save warehouse personnel valuable time. Creating RFID-enabled read locations such as inbound and outbound staging, as well as quality-hold and repair locations, greatly reduces time spent searching for missing products.
New and exciting applications for RFID technology are being devised every day. This article is only meant to provide a glimpse into how companies are currently applying the technology. Every company has its own unique processes and systems. It is important to be creative and think outside the box when designing an RFID system. If you do, the potential is great.
Louis Sirico is an industry-recognized
RFID expert. He has successfully implemented RFID solutions for Target, the Department of Homeland Security,
Kimberly-Clark and numerous Fortune 1000 companies. He is the founder of RFIDWizards.com, an Internet-based community including the world's leading subject matter experts in RFID. He is a founding member of EPCglobal Inc., served as a
subject-matter expert for the CompTIA RFID+ certification exam and was nominated for Entrepreneur of the Year in 2003.